Revealing: During the big fight scene, you can tell easily that the black guy is wearing knee pads (try looking when his pant leg is wet). Construction workers will often wear knee pads for work but most often they wear them on the outside of the pants to save the knees of their pants.

Visible crew/equipment: When Nada is escaping with Holly, you can see the reflection of the film crew on the car.

Continuity: In the big fight scene, Roddy Piper and the black guy are wrestling and struggling about and land so the black guy's pants are getting soaking wet. In the very next shot as the fight continues, his pants are dry.

Continuity: After Roddy Piper's character spends the night at the homeless camp, he walks towards the church wearing a toolbelt. He stops and watches the Street Preacher recite what is airing on television. As the shot switches back from the Preacher to Piper, his tool belt has vanished.